As often occurs, a hernia is formed when the abdominal wall has a weak area that is not capable of keeping the peritoneum in place. When a hernia occurs, a bulge in the peritoneum, called a hernial sac, penetrates through an aperture or opening, called a hernial ring, in the abdominal wall. In corrective surgery, the hernial sac is passed back through and away from the hernial ring. To prevent the hernia from recurring, a barrier material is commonly positioned over the hernial ring and affixed to the surrounding tissue to block passage of the peritoneum therethrough and to strengthen or reinforce the abdominal wall about the hernial ring.
This strengthening or reinforcing is traditionally accomplished by stitching a piece of tissue across the hernial ring. With recent minimally invasive surgical procedures, hernial ring repair is percutaneously performed with the aid of an endoscope, or more particularly a laparoscope, and one or more trocar access sheaths inserted into the abdominal cavity, thereby avoiding a much more invasive procedure such as open surgery with accompanying trauma to surrounding tissue. Instruments and material are inserted through these trocar access sheaths for effecting the repair. During the minimally invasive laparoscopic procedure, two access sheaths are typically inserted through the peritoneum about the hernial ring to pull barrier material such as synthetic prosthetic mesh through one sheath and to spread the mesh over the hernial ring with a grasper inserted through the other sheath. Following positioning, the mesh is affixed to the abdominal wall with clips or suture material.
A problem with the use of prosthetic mesh is that considerable stress or tension is placed on the mesh since it prevents organs or tissue from protruding through the abdominal or thoracic wall. This tension pulls the sutures anchoring the mesh and causes trauma to the adjacent tissue. Furthermore, the tension may be unevenly distributed over the mesh and sutures. The sutures under severe stress may be torn from the adjacent tissue. Adjacent tissue that is torn or traumatized by stressed sutures impedes new tissue growth over the mesh. In some cases, the adjacent tissue damage enlarges the weak area or hernial ring, and subsequent surgery is required for performing additional repairs.
Another problem is the surgeon's difficulty in grasping and manipulating the mesh. With traditional open surgery, the surgeon has direct access to the weak area or hernial ring, and a piece of mesh is readily positionable thereover. However, once wetted by bodily fluids at the repair site, some meshes are awkward to manipulate. In minimally invasive laparoscopic procedures, a sheet of mesh is folded or rolled for introduction through one of the trocar access sheaths. Again, once wetted by bodily fluids at the repair site, the mesh is difficult to spread smoothly over the repair site.
The problem of positioning the prosthetic mesh in a smooth sheet over the repair site is compounded when the mesh is placed between layers of tissue. The mesh is placed between the transversalis and Poupart's ligament in the well-known subfascial technique for repairing a direct inguinal hernia with weak fascia, for example, and between the peritoneum and transversalis in the well-known two-layer technique for repairing large defects using mattress sutures about the periphery of both sheets of mesh. Furthermore, the mesh is difficult and awkward to smooth into place when sandwiched between these layers.